Fuse receptacle



Oct. 24, 1939. L. J. MOLNER FUSE RECEPTACLE Filed Sept. 8, 193'? INVENTOR ZowJMoZrzer ORNEY Patented Oct. 24, 1939 UNITED STATES EFATENT QFFiCE FUSE RECEPTACLE This invention relates to receptacles for removable fuse holders and the like and has for its object to make such devices more tamper-proof and fool-proof as well as more shock-proof than are existing devices of this class on the market today.

When a plug type fuse blows and the owner or occupant of the premises has no spare fuse plugs on hand, it has been a not infrequent practice for a coin or piece of wire or metal foil to be used temporarily under or in place of the plug that has burned out, thus bridging the connections normally closed by the fuse. A coin such as the penny may be clamped by the old plug type fuse in contact with both the shell and the center contact of the socket receiving the plug. Such a practice is hazardous and troublesome. If the cause of the fuse blowing still exists it may result in excessive heating causing a fire. The heavy current flow may also cause fuses or circuit breakers to open some place in the high voltage primary circuit outside the premises or may even burn out a transformer.

According to this invention it is more difficult to insert a coin or conductor in the receptacle and bridge the contacts when a fuse has blown. Specifically the receptacle is lined on the inside and bottom with insulating material making such bridging practically impossible and a fuse holder is threaded over instead of being placed inside the threaded receptacle shell.

The removable fuse holder is also preferably provided with insulating material on the outside so as to reduce any possibility of electric shock in handling the same during its insertion or withdrawal from the receptacle.

Referring to the drawing:

Fig. 1 is a top plan view of the receptacle and fuse holder in position.

Fig. 2 is a cross section of the fuse holder embodying this invention.

Fig, 3 is a section on the line 33 of Fig. l but with the fuse holder removed.

The receptacle is provided with a base ll] of insulating material such as either porcelain or some molded resinous or other type material. A channel H is provided on one side of the base for reception of the grounded conductor of a two-way line. A channel 12 receives the connections for the ungrounded or fused side of the line. Terminal screws l3 and I4 are located in the channel l2 and are connected respectively to the threaded metal shell [5 and central contact l6 within the shell at the base thereof. A guard wall ll of insulating material encloses the Bridgeport, Conn,

8, 1937, Serial No. 162,842

shell l5 and is preferably formed integral with the base, said wall being open as shown in Figs. 1 and 3 to facilitate insertion of the shell l5 and its connected conductor leading to the terminal screw l3.

Within the shell I5 is another wall l8 of insulating material located substantially contiguous the shell .15. This wall is preferably closed at the bottom 59 except where the contact 26 passes through it. This cylindrical insulating wall l8 l0 and its closed bottom may be of the same material as that of the base ill or may be of some other or different material. This wall is preferably extends up so as to be substantially fiush with the top of the shell 55 although it may, if desired, be slightly longer or shorter as shown, so long as it does not prevent the threaded fuse holder from having its central contact engage the central contact of the receptacle.

Fig. 2 shows the fuse holder or the like having a threaded metal shell 20 adapted to be screwed upon the outside of the shell l5. Contiguous the outside of the shell 2!) is a wall of insulating material 2! preferably of the shape illustrated and formed with an integral central cylindrical portion am. A strip of fusible material 22 is connected between the shell 20 and the central contact 23. This fuse is arranged in any convenient manner so as to be visible through the transparent closure 24 of isinglass or other customarily used material. The wall 26 of insulating material holding the closure 24 is preferably spaced from the fusible link and the wall 21 of insulating material and clamped in position by the rivets 25 illustrated.

To connect the fuse holder with the receptacle the outside of the Wall 2| is grasped and the fuse holder rotated until the shell 29 extends far enough down on the outside of the shell [5 for the contacts it and 23 to be engaged and held firmly together. To remove the fuse holder it is simply unscrewed. The fuse holder of Fig. 2 preferably extends slightly above the wall ll of the receptacle so as to make it easy to remove the fuse holder at any time.

Among the advantages of this invention may be mentioned its enhanced foolproof and tamperproof character since the insulating walls l8 and is make it practically impossible for a conductor to be bridged between the shell 15 and contact IS on the inside of the shell l5. The outside of fuse holder being of insulating material precludes the possibility of accidental shock. The walls 2|, 2la, 26 and 21 may be of the same material as the base ID or of different material.

The device illustrated may be made cheaply and simply. The shells I5 and 20 may each be frictionally retained contiguous their insulating walls or if desired these insulating walls contiguous the shells may be molded so as to fit still closer to the shell than is illustrated in Figs, 2 and 3.

The advantages of this invention may be available for other devices than fuses. In the specific embodiment illustrated a lamp or any device for series connection by a plug and socket type connector may embody this invention.

I claim:

1. The combination with a receptacle, of a fuse holder or the like therefor, the fuse holder comprising a threaded metal shell, a contact axially therein adjacent one end of the shell, a hollow support of insulating material for said contact radially spaced from and within said shell, a fuse connected between said contact and shell and a covering of insulating material on the outside of and substantially contiguous said threaded shell, said receptacle comprising a threaded metal shell, a base of insulating material on which the same is mounted, a central contact at the bottom of the shell but insulated therefrom, terminals on said base connected to said shell and contact, and insulating material within said shell shaped to prevent a conductor bridging said contact and shell on the inside, whereby the shell of the fuse holder may be threaded over the shell of the receptacle.

2. A receptacle for a fuse holder adapted for insertion in one side of a line comprising a base of insulating material having a channel for receiving the grounded conductor and a two-wire line, another channel containing connections for the ungrounded side of the line, an upstanding wall of insulating material across the second mentioned channel and enclosing a threaded conductor shell to which a removable connector is adapted to be screwed on the outside of said shell but within said wall, a contact in the base of said shell but insulated therefrom and an insulating covering on the inside of said threaded shell adapted to prevent a conductor bridging said shell and contact inside the shell.

3. A receptacle for a fuse holder adapted for insertion in one side of a line comprising a base of insulating material having a channel for receiving the grounded conductor of a two-wire line, another channel containing connections for the ungrounded side of the line, an upstanding wall of insulating material across the second mentioned channel and enclosing a threaded conductor shell to which a removable connector is adapted to be screwed on the outside of said shell but within said wall, a contact in the base of said shell but insulated therefrom and an insulating covering on the inside of said threaded shell adapted to prevent a conductor bridging said shell and contact inside the shell, and a fuse holder or the like adapted to connect said contact with the outside of said shell.

4. A receptacle for a fuse holder adapted for insertion in one side of a line comprising a base of insulating material having a channel for receiving the grounded conductor of a two-wire line, another channel containing connections for the ungrounded side of the line, an upstanding wall of insulating material enclosing a threaded conductor shell to which a removable connector is adapted to be screwed on the outside of said shell but within said wall, a contact in the base of said shell but insulated therefrom, an insulating covering on the inside of said threaded shell adapted to prevent a conductor bridging said shell and contact inside the shell, and a fuse holder or the like adapted to connect said contact with the outside of said shell, said fuse holder or the like having a shell threaded over the first mentioned shell and a wall of insulating material around the second mentioned shell adapted to be received within the first mentioned wall.

5. A fuse holder comprising a threaded metal shell, a contact axially therein against one end of the shell, a hollow support of insulating material for said contact radially spaced from and within said shell, a fuse connected between said contact and shell, and a covering of insulating material on the outside of and substantially contiguous said threaded shell.

LOUIS J. MOLNER. 

